The invention relates to improvements in apparatus for surface treatment (such as deburring, cleaning or polishing) of metallic, plastic and/or other workpieces. More particularly, the invention relates to improvements in apparatus of the type disclosed in commonly owned U.S. Pat. Nos. 4,218,854, 4,368,599, 4,757,647 and 4,844,232. The disclosures of these patents are incorporated herein by reference. Apparatus of the type to which the present invention pertains are also disclosed in published European patent applications Nos. 205 738 and 289 845.
Commonly owned U.S. Pat. No. 4,844,232 discloses an apparatus wherein the shell of the cage-like receptacle for workpieces is composed of longitudinally extending cable-like, rope-like, wire-like or rod-like components. The end portions of the components are secured to two end walls which act not unlike wobble plates or swash plates and cause the components to move back and forth in parallelism with the axis of rotation of the receptacle to thus advance the workpieces in the interior of the shell in a direction from the one toward the other axial end of the receptacle. As shown in FIG. 4 of this patent, the connections between the end portions of the components and the end walls include ball joints. Each ball joint includes a socket having a concave surface and a spherical head which extends into the socket and is biased against the concave surface A drawback of such joints is that they are expensive as well as that their parts are subjected to extensive wear when the apparatus is in use. Moreover, such joints are overly affected by certain treating agents for the workpieces in the shell of the receptacle, for example, by certain types of fluids or by certain flowable pulverulent and/or granular solid materials which are propelled against the workpieces to remove burrs, to achieve a certain surface finish and/or for other purposes. Solid particles which penetrate between the socket and the head of a ball joint are likely to rapidly damage or totally destroy the joint. Once a joint fails to function, the respective component is subjected to pronounced bending or flexing stresses whenever the apparatus is put to use, and such repeated flexing causes the material of the component to tire so that the component breaks shortly after partial or complete destruction of the respective ball joint.
OBJECTS OF THE INVENTION
An object of the invention is to provide a novel and improved apparatus which is more rugged and the parts of which can stand more pronounced wear than in heretofore known apparatus
Another object of the invention is to provide a novel and improved receptacle for use in the above outlined apparatus
A further object of the invention is to provide a receptacle wherein the cable-like, rope-like, rod-like, wire-like or analogous components of the shell are connected to the respective end walls in a novel and improved way.
An additional object of the invention is to provide novel and improved joints between the components of the shell and one or both end walls.
Still another object of the invention is to provide joints which are less likely to be affected by work treating agents than heretofore known joints and the useful life of which is much longer than that of ball joints.
A further object of the invention is to provide an apparatus which can be designed for the treatment of relatively small or larger workpieces or of random mixtures of smaller and larger workpieces.
Another object of the invention is to provide an apparatus wherein a relatively small number of specially designed joints suffices to prolong the useful life on the receptacle for workpieces.
An additional object of the invention is to provide a novel and improved shell for use in the receptacle of the above outlined apparatus.
A further object of the invention is to provide a novel and improved method of prolonging the useful life of the receptacle for workpieces which are to be bombarded by particles of solid material, subjected to the action of flames and/or subjected to the action of gaseous and/or liquid fluids during transport through the shell of the receptacle.
Another object of the invention is to provide the apparatus with novel and improved means for limiting the extent of flexing of end portions of rod-like or wire-like components forming part of or constituting the shell of the receptacle for workpieces.